I made a custom food for the sauce, added the steak, spinach, and the rest.

All of those items appear on my list of foods. Would it be possible to have the function on the Foods tab to check each of those individual items, add them up, and save that sum as its own custom food? This would save me the hassle of adding all of those recent foods individually if I have the same thing on a different day.

I could just name it "My subway salad" and it would just display as one food item that has the nutrition facts from all of those foods combined.

I made a custom food for the sauce, added the steak, spinach, and the rest.

All of those items appear on my list of foods. Would it be possible to have the function on the Foods tab to check each of those individual items, add them up, and save that sum as its own custom food? This would save me the hassle of adding all of those recent foods individually if I have the same thing on a different day.

I could just name it "My subway salad" and it would just display as one food item that has the nutrition facts from all of those foods combined.

What you are asking for, if I understand you correctly, is a recipe builder. All you need to know is here, in Post #4